Timo Werner has admitted his Chelsea goal drought was 'the worst time of my career' and that he 'felt guilty' after his missed chances led to Frank Lampard getting the sack.
The German striker, who cost Chelsea £47.5million last summer, went 14 Premier League matches without a goal between November 7 and February 15.
During that time, Chelsea saw a potential title challenge disintegrate following a run of five defeats in eight games that saw club legend Lampard replaced by Thomas Tuchel.
His barren league run finally ended with a goal in Chelsea's 2-0 win over Newcastle United just under two weeks ago though Werner did score against League Two Morecambe in the FA Cup in January.
Werner's game has picked up again since compatriot Tuchel was appointed manager and he has also set up three other goals in recent weeks.
'The period where I didn't score was the worst time of my career because I'd never missed so many big chances,' Werner told Sky Sports ahead of Chelsea's meeting with Manchester United on Sunday.
'I'd never been so long without a goal, so I was very happy it ended two games ago.
'The smile wasn't on my face all the time. You have to keep smiling, that's the most important thing because when you are not happy and you don't enjoy football, and you are always angry or mad, you can't go back to moments where you can play good football.'
Lampard was sacked after a poor run of just four wins in 11 games and Werner admitted he was partly responsible for his dismissal.
He said: 'When you come here to play as a striker and be the man to score the goals, of course I felt a little bit guilty that I missed so many chances.
'For the club, for the old manager but also for me because I want to score all the time as much as I possibly can.
'Of course, if I'd scored four or five more goals maybe the old manager would still be here because we'd maybe have won two or three games more but you can't look too much into the past because there are too many games ahead of us.'
Having joined from RB Leipzig last summer, Werner readily admits the Premier League is more demanding that the Bundesliga and has proved tougher than he imagined.
'What I get now is that the Premier League is really hard,' he said. 'Every game, whether you play against the bottom side or the third side, it's always the same game.'
Three points against Man United on Sunday would move Chelsea above London rivals West Ham and into the top four once again.